perlsource may have some clues

Thanks afoken ... that's what I needed to read.

I was being thrown by the fact that the dual-life module threads, located in the "dist" directory of the perl source, is currently at version 2.28 (2.27 in perl-5.36.0 source), yet CPAN stops at version 2.21 (from Jan 2018).
But it turns out this is totally allowable under the perlsource spec for files located in the "dist" directory ... though I'm going to have a serious rethink about the meaning of "dual-life".
If a "dual-life" module is going to remain at version 2.21 on CPAN forever more (either in order to remain backwards-compatible, or because no-one can be bothered updating the CPAN version), is it really "dual-life" ? What sort of a "dual" life is that ?
To quote InfiniteSilence: "Might want to ask the Perl Porters that question" ;-)

Cheers,
Rob